Astronomy and Stars
Discussions about astronomy and stars. As we look further out what can we find in the universe beyond Earth's atmosphere?
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Using its near-infrared vision to peer 9 billion years back in time, NASA's Hubble Space Telescope has uncovered an extraordinary population of tiny, young galaxies that are brimming with star formation. The galaxies are typically a hundred times less massive than the Milky Way galaxy, yet they churn out stars at such a furious pace that their stellar content would double in just 10 million years. By comparison, the Milky Way would take a thousand times longer to double its population. The observations were part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), an ambitious three-year survey to analyze the most distant galaxies in the univ…
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Writing in the Nov. 10 issue of the journal Nature, Space Telescope Science Institute astrophysicist Mario Livio solves the mystery of why paragraphs disappeared during the 1931 translation of Belgian cosmologist Georges Lemaître's remarkable 1927 paper showing that the universe is expanding. For nearly a century, American astronomer Edwin Hubble has held the fame for this landmark discovery, which would recast all of 20th century astronomy. After going through hundreds of pieces of correspondence of the Royal Astronomical Society, as well as minutes of the RAS meetings, and material from the Lemaître Archive, Livio has discovered that Lemaître omitted the passages himsel…
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A new analysis of Hubble surveys, including the All-Wavelength Extended Groth Strip International Survey (AEGIS), the Cosmological Evolution Survey (COSMOS), and the Great Observatories Origins Deep Survey (GOODS), combined with simulations of galaxy interactions, reveals that the merger rate of galaxies over the last 8 billion to 9 billion years falls between previous estimates. The galaxy merger rate is one of the fundamental measures of galaxy evolution, yielding clues to how galaxies bulked up over time through encounters with other galaxies. And yet, a huge discrepancy exists over how often galaxies coalesced in the past. Earlier measurements of galaxies in deep-fi…
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Cluster MACS J1206.2-0847 (or MACS 1206 for short) is one of the first targets in a Hubble Space Telescope survey that will allow astronomers to construct the highly detailed dark matter maps of more galaxy clusters than ever before. These maps are being used to test previous but surprising results that suggest that dark matter is more densely packed inside galaxy clusters than some models predict. This might mean that galaxy cluster assembly began earlier than commonly thought. The multiwavelength survey, called the Cluster Lensing And Supernova survey with Hubble (CLASH), probes, with unparalleled precision, the distribution of dark matter in 25 massive clusters of gala…
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Baltimore's Maryland Science Center is going to be the "landing site" for the full-scale model of NASA's James Webb Space Telescope, and it's free for all to see. The Webb telescope life-sized model is as big as a tennis court, and it's coming to the Maryland Science Center at Baltimore's Inner Harbor from October 14 through 26, 2011. It's a chance for young and old to get a close-up look at the successor to the Hubble Space Telescope in the same size it will be launched into space. Experts will be on hand to discuss the Webb telescope's deep-space mission, how it will observe distant galaxies and nearby stars and planets, and the progress made to date in building the obs…
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In a painstaking re-analysis of Hubble Space Telescope images from 1998, astronomers have found visual evidence for two extrasolar planets that went undetected back then. Finding these hidden gems in the Hubble archive gives astronomers an invaluable time machine for comparing much earlier planet orbital motion data to more recent observations. It also demonstrates a novel approach for planet hunting in archival Hubble data. View the full article
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Adam Riess, an astronomer at the Space Telescope Science Institute (STScI) and Krieger-Eisenhower Professor in Physics and Astronomy at The Johns Hopkins University in Baltimore, today was awarded the 2011 Nobel Prize in Physics by the Royal Swedish Academy of Sciences. The academy recognized him for leadership in the High-z Team's 1998 discovery that the expansion rate of the universe is accelerating, a phenomenon widely attributed to a mysterious, unexplained "dark energy" filling the universe. View the full article
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An international team of astronomers using five different telescopes has uncovered striking features around a supermassive black hole in the core of the distant galaxy Markarian 509. They found a very hot corona hovering above the black hole and cold gas "bullets" in hotter diffuse gas, speeding outward with velocities over 1 million miles per hour. This corona absorbs and reprocesses the ultraviolet light from the accretion disk encircling the black hole, energizing it and converting it into X-rays. This discovery allows astronomers to make sense of some of the observations of active galaxies that have been hard to explain so far. The heart of the campaign consisted of r…
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Beginning on Sunday, September 25 an outdoor laser exhibit at the Maryland Science Center will present a unique blend of astronomy and art. Hubble spectral observations of distant galaxies will be projected onto the Maryland Science Center with an intense green laser. Educational activities will allow students to explore the world of light and color in astronomy. View the full article
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Using the slitless grism on Hubble Space Telescope's Wide Field Camera 3 to probe the distant universe, astronomers have found supermassive black holes growing in surprisingly small galaxies. The findings suggest that central black holes formed at an earlier stage in galaxy evolution. This study is part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and will be published in the Astrophysical Journal. View the full article
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A team of scientists has collected enough high-resolution Hubble Space Telescope images over a 14-year period to stitch together time-lapse movies of powerful jets ejected from three young stars. The jets, a byproduct of gas accretion around newly forming stars, shoot off at supersonic speeds in opposite directions through space. These phenomena are providing clues about the final stages of a star's birth, offering a peek at how our Sun came into existence 4.5 billion years ago. Hubble's unprecedented sharpness allows astronomers to see changes in the jets over just a few years' time. Most astronomical processes change over timescales that are much longer than a human l…
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The long-term forecast for the Milky Way is cloudy with gaseous rain. A study by Nicolas Lehner and Christopher Howk of the University of Notre Dame concludes that massive clouds of ionized gas are raining down from our galaxy's halo and intergalactic space and will continue to provide fuel for the Milky Way to keep forming stars. Using the Hubble Space Telescope's Cosmic Origins Spectrograph they measured for the first time the distances to huge, fast-moving clouds of ionized gas previously seen covering a large fraction of the sky. View the full article
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A giant cosmic necklace glows brightly in this NASA Hubble Space Telescope image. The object, aptly named the Necklace Nebula, is a recently discovered planetary nebula, the glowing remains of an ordinary, Sun-like star. The nebula consists of a bright ring, measuring 12 trillion miles across, dotted with dense, bright knots of gas that resemble diamonds in a necklace. The knots glow brightly due to absorption of ultraviolet light from the central stars. The Necklace Nebula is located 15,000 light-years away in the constellation Sagitta (the Arrow). In this composite image, taken on July 2, 2011, Hubble's Wide Field Camera 3 captured the glow of hydrogen (blue), oxygen …
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These two images, taken about a week apart by NASA's Hubble Space Telescope, show four moons orbiting the distant, icy dwarf planet Pluto. The green circle in both snapshots marks the newly discovered moon, temporarily dubbed P4, found by Hubble in June. P4 is the smallest moon yet found around Pluto, with an estimated diameter of 8 to 21 miles (13 to 34 km). By comparison, Pluto's largest moon Charon is 746 miles (1,200 km) across. Nix and Hydra are 20 to 70 miles (32 to 113 km) wide. The new moon lies between the orbits of Nix and Hydra, two satellites discovered by Hubble in 2005. P4 completes an orbit around Pluto roughly every 31 days. The new moon was first seen i…
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These four images of Neptune were taken by NASA's Hubble Space Telescope during the planet's 16-hour rotation. The snapshots were taken at roughly four-hour intervals, offering a full view of the blue-green planet. Today marks Neptune's first orbit around the Sun since it was discovered nearly 165 years ago. These images were taken to commemorate the event. The Hubble images, taken with the Wide Field Camera 3 on June 25-26, reveal high-altitude clouds in the northern and southern hemispheres. The clouds are composed of methane ice crystals. In the Hubble images, absorption of red light by methane in Neptune's atmosphere gives the planet its distinctive aqua color. The …
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NASA's Hubble Space Telescope crossed another milestone in its 21-year space odyssey of exploration and discovery. On Monday, July 4, the Earth-orbiting observatory logged its one millionth science observation during a search for water in an exoplanet's atmosphere 1,000 light-years away. Although Hubble is best known for its stunning imagery of the cosmos, the millionth exposure is a spectroscopic measurement, where light is divided into its component colors. These color patterns can reveal the chemical composition of cosmic sources. This is an artist's concept of Hubble's millionth exposure, the extrasolar planet HAT-P-7b. It is a gas planet larger than Jupiter orbiting …
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A team of scientists studying the galaxy cluster Abell 2744, nicknamed Pandora's Cluster, have pieced together the cluster's complex and violent history using telescopes in space and on the ground, including the Hubble Space Telescope, the European Southern Observatory's Very Large Telescope, the Japanese Subaru telescope, and NASA's Chandra X-ray Observatory. The giant galaxy cluster appears to be the result of a simultaneous pile-up of at least four separate, smaller galaxy clusters that took place over a span of 350 million years. The galaxies in the cluster make up less than five percent of its mass. The gas (around 20 percent) is so hot that it shines only in X-ray…
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Resembling looming rain clouds on a stormy day, dark lanes of dust crisscross the giant elliptical galaxy Centaurus A. Hubble's panchromatic vision, stretching from ultraviolet through near-infrared wavelengths, reveals the vibrant glow of young, blue star clusters and a glimpse into regions normally obscured by the dust. This image was taken in July 2010 with Hubble's Wide Field Camera 3. View the full article
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Astronomers using NASA's Hubble Space Telescope are witnessing the unprecedented transition of a supernova to a supernova remnant, where light from an exploding star in a neighboring galaxy, the Large Magellanic Cloud, reached Earth in February 1987. Named Supernova 1987A, it was the closest supernova explosion witnessed in almost 400 years. The supernova's close proximity to Earth has allowed astronomers to study it in detail as it evolves. Now, the supernova debris, which has faded over the years, is brightening. This means that a different power source has begun to light the debris. The debris of SN 1987A is beginning to impact the surrounding ring, creating powerful s…
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Peering deep into the star-filled, ancient hub of our Milky Way (left), NASA's Hubble Space Telescope has found a rare class of oddball stars called blue stragglers. This is the first time such objects have been detected within our galaxy's bulge. Blue stragglers are so named because they seem to be lagging behind in their rate of aging compared with nearby older stars. The discovery is a spin-off from a seven-day-long survey conducted in 2006 called the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS). Hubble peered at and obtained variability information for 180,000 stars in the crowded central bulge of our galaxy, 26,000 light-years away. View th…
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Though the universe is filled with billions upon billions of stars, NASA's Hubble Space Telescope has been trained on a single variable star that in 1923 altered the course of modern astronomy. And, at least one famous astronomer of the time lamented that the discovery had shattered his world view. The star goes by the inauspicious name of Hubble variable number one, or V1, and resides two million light-years away in the outer regions of the neighboring Andromeda galaxy, or M31. V1 is a special class of pulsating star called a Cepheid variable that can be used to make reliable measurements of large cosmic distances. The star helped Edwin Hubble show that Andromeda lies be…
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The dwarf galaxy NGC 4214 is ablaze with young stars and gas clouds. Located around 10 million light-years away in the constellation of Canes Venatici (The Hunting Dogs), the galaxy's close proximity, combined with the wide variety of evolutionary stages among the stars, make it an ideal laboratory to research the triggers of star formation and evolution. This color image was taken using the Hubble Space Telescope's Wide Field Camera 3 in December 2009. View the full article
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Late last year, astronomers noticed an asteroid named Scheila had unexpectedly brightened, and it was sporting short-lived plumes. Data from NASA's Swift satellite and Hubble Space Telescope showed these changes likely occurred after Scheila was struck by a much smaller asteroid. This visible-light image of asteroid (596) Scheila was taken with Hubble's Wide Field Camera 3 on Dec. 27, 2010, when the asteroid was approximately 217 million miles away. The asteroid is surrounded by a C-shaped cloud, or coma, of dust particles. The asteroid body, which is approximately 70 miles across, appears star-like because it is overexposed so that the faint dust can be imaged. …
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To celebrate the 21st anniversary of the Hubble Space Telescope's deployment into space, astronomers at the Space Telescope Science Institute in Baltimore, Md., pointed Hubble's eye at an especially photogenic pair of interacting galaxies called Arp 273. The larger of the spiral galaxies, known as UGC 1810, has a disk that is distorted into a rose-like shape by the gravitational tidal pull of the companion galaxy below it, known as UGC 1813. This image is a composite of Hubble Wide Field Camera 3 data taken on December 17, 2010, with three separate filters that allow a broad range of wavelengths covering the ultraviolet, blue, and red portions of the spectrum. Hubble wa…
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Astronomers have uncovered one of the youngest galaxies in the distant universe, with stars that formed 13.5 billion years ago, a mere 200 million years after the Big Bang. The finding addresses questions about when the first galaxies arose, and how the early universe evolved. NASA's Hubble Space Telescope was the first to spot the newfound galaxy. Detailed observations from the W.M. Keck Observatory on Mauna Kea in Hawaii revealed the observed light dates to when the universe was only 950 million years old; the universe formed about 13.7 billion years ago. Infrared data from both Hubble and NASA's Spitzer Space Telescope revealed the galaxy's stars are quite mature, havi…
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